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<a name="glib-Data-HMACs"></a><div class="titlepage"></div>
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<h2><span class="refentrytitle"><a name="glib-Data-HMACs.top_of_page"></a>Secure HMAC Digests</span></h2>
<p>Secure HMAC Digests — computes the HMAC for data</p>
</td>
<td class="gallery_image" valign="top" align="right"></td>
</tr></table></div>
<div class="refsect1">
<a name="glib-Data-HMACs.functions"></a><h2>Functions</h2>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="functions_return">
<col class="functions_name">
</colgroup>
<tbody>
<tr>
<td class="function_type">
<a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="returnvalue">GHmac</span></a> *
</td>
<td class="function_name">
<a class="link" href="glib-Data-HMACs.html#g-hmac-new" title="g_hmac_new ()">g_hmac_new</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="returnvalue">GHmac</span></a> *
</td>
<td class="function_name">
<a class="link" href="glib-Data-HMACs.html#g-hmac-copy" title="g_hmac_copy ()">g_hmac_copy</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="returnvalue">GHmac</span></a> *
</td>
<td class="function_name">
<a class="link" href="glib-Data-HMACs.html#g-hmac-ref" title="g_hmac_ref ()">g_hmac_ref</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="glib-Data-HMACs.html#g-hmac-unref" title="g_hmac_unref ()">g_hmac_unref</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="glib-Data-HMACs.html#g-hmac-update" title="g_hmac_update ()">g_hmac_update</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">const <a class="link" href="glib-Basic-Types.html#gchar" title="gchar"><span class="returnvalue">gchar</span></a> *
</td>
<td class="function_name">
<a class="link" href="glib-Data-HMACs.html#g-hmac-get-string" title="g_hmac_get_string ()">g_hmac_get_string</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<span class="returnvalue">void</span>
</td>
<td class="function_name">
<a class="link" href="glib-Data-HMACs.html#g-hmac-get-digest" title="g_hmac_get_digest ()">g_hmac_get_digest</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a class="link" href="glib-Basic-Types.html#gchar" title="gchar"><span class="returnvalue">gchar</span></a> *
</td>
<td class="function_name">
<a class="link" href="glib-Data-HMACs.html#g-compute-hmac-for-data" title="g_compute_hmac_for_data ()">g_compute_hmac_for_data</a> <span class="c_punctuation">()</span>
</td>
</tr>
<tr>
<td class="function_type">
<a class="link" href="glib-Basic-Types.html#gchar" title="gchar"><span class="returnvalue">gchar</span></a> *
</td>
<td class="function_name">
<a class="link" href="glib-Data-HMACs.html#g-compute-hmac-for-string" title="g_compute_hmac_for_string ()">g_compute_hmac_for_string</a> <span class="c_punctuation">()</span>
</td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect1">
<a name="glib-Data-HMACs.other"></a><h2>Types and Values</h2>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="name">
<col class="description">
</colgroup>
<tbody><tr>
<td class="datatype_keyword"> </td>
<td class="function_name"><a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac">GHmac</a></td>
</tr></tbody>
</table></div>
</div>
<div class="refsect1">
<a name="glib-Data-HMACs.includes"></a><h2>Includes</h2>
<pre class="synopsis">#include &lt;glib.h&gt;
</pre>
</div>
<div class="refsect1">
<a name="glib-Data-HMACs.description"></a><h2>Description</h2>
<p>HMACs should be used when producing a cookie or hash based on data
and a key. Simple mechanisms for using SHA1 and other algorithms to
digest a key and data together are vulnerable to various security
issues.
<a class="ulink" href="http://en.wikipedia.org/wiki/HMAC" target="_top">HMAC</a>
uses algorithms like SHA1 in a secure way to produce a digest of a
key and data.</p>
<p>Both the key and data are arbitrary byte arrays of bytes or characters.</p>
<p>Support for HMAC Digests has been added in GLib 2.30, and support for SHA-512
in GLib 2.42.</p>
</div>
<div class="refsect1">
<a name="glib-Data-HMACs.functions_details"></a><h2>Functions</h2>
<div class="refsect2">
<a name="g-hmac-new"></a><h3>g_hmac_new ()</h3>
<pre class="programlisting"><a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="returnvalue">GHmac</span></a> *
g_hmac_new (<em class="parameter"><code><a class="link" href="glib-Data-Checksums.html#GChecksumType" title="enum GChecksumType"><span class="type">GChecksumType</span></a> digest_type</code></em>,
            <em class="parameter"><code>const <a class="link" href="glib-Basic-Types.html#guchar" title="guchar"><span class="type">guchar</span></a> *key</code></em>,
            <em class="parameter"><code><a class="link" href="glib-Basic-Types.html#gsize" title="gsize"><span class="type">gsize</span></a> key_len</code></em>);</pre>
<p>Creates a new <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a>, using the digest algorithm <em class="parameter"><code>digest_type</code></em>
.
If the <em class="parameter"><code>digest_type</code></em>
 is not known, <a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a> is returned.
A <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a> can be used to compute the HMAC of a key and an
arbitrary binary blob, using different hashing algorithms.</p>
<p>A <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a> works by feeding a binary blob through <a class="link" href="glib-Data-HMACs.html#g-hmac-update" title="g_hmac_update ()"><code class="function">g_hmac_update()</code></a>
until the data is complete; the digest can then be extracted
using <a class="link" href="glib-Data-HMACs.html#g-hmac-get-string" title="g_hmac_get_string ()"><code class="function">g_hmac_get_string()</code></a>, which will return the checksum as a
hexadecimal string; or <a class="link" href="glib-Data-HMACs.html#g-hmac-get-digest" title="g_hmac_get_digest ()"><code class="function">g_hmac_get_digest()</code></a>, which will return a
array of raw bytes. Once either <a class="link" href="glib-Data-HMACs.html#g-hmac-get-string" title="g_hmac_get_string ()"><code class="function">g_hmac_get_string()</code></a> or
<a class="link" href="glib-Data-HMACs.html#g-hmac-get-digest" title="g_hmac_get_digest ()"><code class="function">g_hmac_get_digest()</code></a> have been called on a <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a>, the HMAC
will be closed and it won't be possible to call <a class="link" href="glib-Data-HMACs.html#g-hmac-update" title="g_hmac_update ()"><code class="function">g_hmac_update()</code></a>
on it anymore.</p>
<p>Support for digests of type <a class="link" href="glib-Data-Checksums.html#G-CHECKSUM-SHA512:CAPS"><code class="literal">G_CHECKSUM_SHA512</code></a> has been added in GLib 2.42.</p>
<div class="refsect3">
<a name="g-hmac-new.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>digest_type</p></td>
<td class="parameter_description"><p>the desired type of digest</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>key</p></td>
<td class="parameter_description"><p> the key for the HMAC. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter points to an array of items."><span class="acronym">array</span></acronym> length=key_len]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>key_len</p></td>
<td class="parameter_description"><p>the length of the keys</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="g-hmac-new.returns"></a><h4>Returns</h4>
<p> the newly created <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a>, or <a class="link" href="glib-Standard-Macros.html#NULL:CAPS" title="NULL"><code class="literal">NULL</code></a>.
Use <a class="link" href="glib-Data-HMACs.html#g-hmac-unref" title="g_hmac_unref ()"><code class="function">g_hmac_unref()</code></a> to free the memory allocated by it.</p>
</div>
<p class="since">Since: <a class="link" href="api-index-2-30.html#api-index-2.30">2.30</a></p>
</div>
<hr>
<div class="refsect2">
<a name="g-hmac-copy"></a><h3>g_hmac_copy ()</h3>
<pre class="programlisting"><a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="returnvalue">GHmac</span></a> *
g_hmac_copy (<em class="parameter"><code>const <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a> *hmac</code></em>);</pre>
<p>Copies a <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a>. If <em class="parameter"><code>hmac</code></em>
 has been closed, by calling
<a class="link" href="glib-Data-HMACs.html#g-hmac-get-string" title="g_hmac_get_string ()"><code class="function">g_hmac_get_string()</code></a> or <a class="link" href="glib-Data-HMACs.html#g-hmac-get-digest" title="g_hmac_get_digest ()"><code class="function">g_hmac_get_digest()</code></a>, the copied
HMAC will be closed as well.</p>
<div class="refsect3">
<a name="g-hmac-copy.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>hmac</p></td>
<td class="parameter_description"><p>the <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a> to copy</p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="g-hmac-copy.returns"></a><h4>Returns</h4>
<p> the copy of the passed <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a>. Use <a class="link" href="glib-Data-HMACs.html#g-hmac-unref" title="g_hmac_unref ()"><code class="function">g_hmac_unref()</code></a>
when finished using it.</p>
</div>
<p class="since">Since: <a class="link" href="api-index-2-30.html#api-index-2.30">2.30</a></p>
</div>
<hr>
<div class="refsect2">
<a name="g-hmac-ref"></a><h3>g_hmac_ref ()</h3>
<pre class="programlisting"><a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="returnvalue">GHmac</span></a> *
g_hmac_ref (<em class="parameter"><code><a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a> *hmac</code></em>);</pre>
<p>Atomically increments the reference count of <em class="parameter"><code>hmac</code></em>
 by one.</p>
<p>This function is MT-safe and may be called from any thread.</p>
<div class="refsect3">
<a name="g-hmac-ref.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>hmac</p></td>
<td class="parameter_description"><p>a valid <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a></p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="g-hmac-ref.returns"></a><h4>Returns</h4>
<p> the passed in <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a>.</p>
</div>
<p class="since">Since: <a class="link" href="api-index-2-30.html#api-index-2.30">2.30</a></p>
</div>
<hr>
<div class="refsect2">
<a name="g-hmac-unref"></a><h3>g_hmac_unref ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
g_hmac_unref (<em class="parameter"><code><a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a> *hmac</code></em>);</pre>
<p>Atomically decrements the reference count of <em class="parameter"><code>hmac</code></em>
 by one.</p>
<p>If the reference count drops to 0, all keys and values will be
destroyed, and all memory allocated by the hash table is released.
This function is MT-safe and may be called from any thread.
Frees the memory allocated for <em class="parameter"><code>hmac</code></em>
.</p>
<div class="refsect3">
<a name="g-hmac-unref.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>hmac</p></td>
<td class="parameter_description"><p>a <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a></p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<p class="since">Since: <a class="link" href="api-index-2-30.html#api-index-2.30">2.30</a></p>
</div>
<hr>
<div class="refsect2">
<a name="g-hmac-update"></a><h3>g_hmac_update ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
g_hmac_update (<em class="parameter"><code><a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a> *hmac</code></em>,
               <em class="parameter"><code>const <a class="link" href="glib-Basic-Types.html#guchar" title="guchar"><span class="type">guchar</span></a> *data</code></em>,
               <em class="parameter"><code><a class="link" href="glib-Basic-Types.html#gssize" title="gssize"><span class="type">gssize</span></a> length</code></em>);</pre>
<p>Feeds <em class="parameter"><code>data</code></em>
 into an existing <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a>.</p>
<p>The HMAC must still be open, that is <a class="link" href="glib-Data-HMACs.html#g-hmac-get-string" title="g_hmac_get_string ()"><code class="function">g_hmac_get_string()</code></a> or
<a class="link" href="glib-Data-HMACs.html#g-hmac-get-digest" title="g_hmac_get_digest ()"><code class="function">g_hmac_get_digest()</code></a> must not have been called on <em class="parameter"><code>hmac</code></em>
.</p>
<div class="refsect3">
<a name="g-hmac-update.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>hmac</p></td>
<td class="parameter_description"><p>a <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a></p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>data</p></td>
<td class="parameter_description"><p> buffer used to compute the checksum. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter points to an array of items."><span class="acronym">array</span></acronym> length=length]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>length</p></td>
<td class="parameter_description"><p>size of the buffer, or -1 if it is a nul-terminated string</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<p class="since">Since: <a class="link" href="api-index-2-30.html#api-index-2.30">2.30</a></p>
</div>
<hr>
<div class="refsect2">
<a name="g-hmac-get-string"></a><h3>g_hmac_get_string ()</h3>
<pre class="programlisting">const <a class="link" href="glib-Basic-Types.html#gchar" title="gchar"><span class="returnvalue">gchar</span></a> *
g_hmac_get_string (<em class="parameter"><code><a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a> *hmac</code></em>);</pre>
<p>Gets the HMAC as an hexadecimal string.</p>
<p>Once this function has been called the <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a> can no longer be
updated with <a class="link" href="glib-Data-HMACs.html#g-hmac-update" title="g_hmac_update ()"><code class="function">g_hmac_update()</code></a>.</p>
<p>The hexadecimal characters will be lower case.</p>
<div class="refsect3">
<a name="g-hmac-get-string.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody><tr>
<td class="parameter_name"><p>hmac</p></td>
<td class="parameter_description"><p>a <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a></p></td>
<td class="parameter_annotations"> </td>
</tr></tbody>
</table></div>
</div>
<div class="refsect3">
<a name="g-hmac-get-string.returns"></a><h4>Returns</h4>
<p> the hexadecimal representation of the HMAC. The
returned string is owned by the HMAC and should not be modified
or freed.</p>
</div>
<p class="since">Since: <a class="link" href="api-index-2-30.html#api-index-2.30">2.30</a></p>
</div>
<hr>
<div class="refsect2">
<a name="g-hmac-get-digest"></a><h3>g_hmac_get_digest ()</h3>
<pre class="programlisting"><span class="returnvalue">void</span>
g_hmac_get_digest (<em class="parameter"><code><a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a> *hmac</code></em>,
                   <em class="parameter"><code><a class="link" href="glib-Basic-Types.html#guint8" title="guint8"><span class="type">guint8</span></a> *buffer</code></em>,
                   <em class="parameter"><code><a class="link" href="glib-Basic-Types.html#gsize" title="gsize"><span class="type">gsize</span></a> *digest_len</code></em>);</pre>
<p>Gets the digest from <em class="parameter"><code>checksum</code></em>
 as a raw binary array and places it
into <em class="parameter"><code>buffer</code></em>
. The size of the digest depends on the type of checksum.</p>
<p>Once this function has been called, the <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a> is closed and can
no longer be updated with <a class="link" href="glib-Data-Checksums.html#g-checksum-update" title="g_checksum_update ()"><code class="function">g_checksum_update()</code></a>.</p>
<div class="refsect3">
<a name="g-hmac-get-digest.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>hmac</p></td>
<td class="parameter_description"><p>a <a class="link" href="glib-Data-HMACs.html#GHmac" title="GHmac"><span class="type">GHmac</span></a></p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>buffer</p></td>
<td class="parameter_description"><p>output buffer</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>digest_len</p></td>
<td class="parameter_description"><p>an inout parameter. The caller initializes it to the
size of <em class="parameter"><code>buffer</code></em>
. After the call it contains the length of the digest</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<p class="since">Since: <a class="link" href="api-index-2-30.html#api-index-2.30">2.30</a></p>
</div>
<hr>
<div class="refsect2">
<a name="g-compute-hmac-for-data"></a><h3>g_compute_hmac_for_data ()</h3>
<pre class="programlisting"><a class="link" href="glib-Basic-Types.html#gchar" title="gchar"><span class="returnvalue">gchar</span></a> *
g_compute_hmac_for_data (<em class="parameter"><code><a class="link" href="glib-Data-Checksums.html#GChecksumType" title="enum GChecksumType"><span class="type">GChecksumType</span></a> digest_type</code></em>,
                         <em class="parameter"><code>const <a class="link" href="glib-Basic-Types.html#guchar" title="guchar"><span class="type">guchar</span></a> *key</code></em>,
                         <em class="parameter"><code><a class="link" href="glib-Basic-Types.html#gsize" title="gsize"><span class="type">gsize</span></a> key_len</code></em>,
                         <em class="parameter"><code>const <a class="link" href="glib-Basic-Types.html#guchar" title="guchar"><span class="type">guchar</span></a> *data</code></em>,
                         <em class="parameter"><code><a class="link" href="glib-Basic-Types.html#gsize" title="gsize"><span class="type">gsize</span></a> length</code></em>);</pre>
<p>Computes the HMAC for a binary <em class="parameter"><code>data</code></em>
 of <em class="parameter"><code>length</code></em>
. This is a
convenience wrapper for <a class="link" href="glib-Data-HMACs.html#g-hmac-new" title="g_hmac_new ()"><code class="function">g_hmac_new()</code></a>, <a class="link" href="glib-Data-HMACs.html#g-hmac-get-string" title="g_hmac_get_string ()"><code class="function">g_hmac_get_string()</code></a>
and <a class="link" href="glib-Data-HMACs.html#g-hmac-unref" title="g_hmac_unref ()"><code class="function">g_hmac_unref()</code></a>.</p>
<p>The hexadecimal string returned will be in lower case.</p>
<div class="refsect3">
<a name="g-compute-hmac-for-data.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>digest_type</p></td>
<td class="parameter_description"><p>a <a class="link" href="glib-Data-Checksums.html#GChecksumType" title="enum GChecksumType"><span class="type">GChecksumType</span></a> to use for the HMAC</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>key</p></td>
<td class="parameter_description"><p> the key to use in the HMAC. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter points to an array of items."><span class="acronym">array</span></acronym> length=key_len]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>key_len</p></td>
<td class="parameter_description"><p>the length of the key</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>data</p></td>
<td class="parameter_description"><p>binary blob to compute the HMAC of</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>length</p></td>
<td class="parameter_description"><p>length of <em class="parameter"><code>data</code></em>
</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="g-compute-hmac-for-data.returns"></a><h4>Returns</h4>
<p> the HMAC of the binary data as a string in hexadecimal.
The returned string should be freed with <a class="link" href="glib-Memory-Allocation.html#g-free" title="g_free ()"><code class="function">g_free()</code></a> when done using it.</p>
</div>
<p class="since">Since: <a class="link" href="api-index-2-30.html#api-index-2.30">2.30</a></p>
</div>
<hr>
<div class="refsect2">
<a name="g-compute-hmac-for-string"></a><h3>g_compute_hmac_for_string ()</h3>
<pre class="programlisting"><a class="link" href="glib-Basic-Types.html#gchar" title="gchar"><span class="returnvalue">gchar</span></a> *
g_compute_hmac_for_string (<em class="parameter"><code><a class="link" href="glib-Data-Checksums.html#GChecksumType" title="enum GChecksumType"><span class="type">GChecksumType</span></a> digest_type</code></em>,
                           <em class="parameter"><code>const <a class="link" href="glib-Basic-Types.html#guchar" title="guchar"><span class="type">guchar</span></a> *key</code></em>,
                           <em class="parameter"><code><a class="link" href="glib-Basic-Types.html#gsize" title="gsize"><span class="type">gsize</span></a> key_len</code></em>,
                           <em class="parameter"><code>const <a class="link" href="glib-Basic-Types.html#gchar" title="gchar"><span class="type">gchar</span></a> *str</code></em>,
                           <em class="parameter"><code><a class="link" href="glib-Basic-Types.html#gssize" title="gssize"><span class="type">gssize</span></a> length</code></em>);</pre>
<p>Computes the HMAC for a string.</p>
<p>The hexadecimal string returned will be in lower case.</p>
<div class="refsect3">
<a name="g-compute-hmac-for-string.parameters"></a><h4>Parameters</h4>
<div class="informaltable"><table class="informaltable" width="100%" border="0">
<colgroup>
<col width="150px" class="parameters_name">
<col class="parameters_description">
<col width="200px" class="parameters_annotations">
</colgroup>
<tbody>
<tr>
<td class="parameter_name"><p>digest_type</p></td>
<td class="parameter_description"><p>a <a class="link" href="glib-Data-Checksums.html#GChecksumType" title="enum GChecksumType"><span class="type">GChecksumType</span></a> to use for the HMAC</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>key</p></td>
<td class="parameter_description"><p> the key to use in the HMAC. </p></td>
<td class="parameter_annotations"><span class="annotation">[<acronym title="Parameter points to an array of items."><span class="acronym">array</span></acronym> length=key_len]</span></td>
</tr>
<tr>
<td class="parameter_name"><p>key_len</p></td>
<td class="parameter_description"><p>the length of the key</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>str</p></td>
<td class="parameter_description"><p>the string to compute the HMAC for</p></td>
<td class="parameter_annotations"> </td>
</tr>
<tr>
<td class="parameter_name"><p>length</p></td>
<td class="parameter_description"><p>the length of the string, or -1 if the string is nul-terminated</p></td>
<td class="parameter_annotations"> </td>
</tr>
</tbody>
</table></div>
</div>
<div class="refsect3">
<a name="g-compute-hmac-for-string.returns"></a><h4>Returns</h4>
<p> the HMAC as a hexadecimal string.
The returned string should be freed with <a class="link" href="glib-Memory-Allocation.html#g-free" title="g_free ()"><code class="function">g_free()</code></a>
when done using it.</p>
</div>
<p class="since">Since: <a class="link" href="api-index-2-30.html#api-index-2.30">2.30</a></p>
</div>
</div>
<div class="refsect1">
<a name="glib-Data-HMACs.other_details"></a><h2>Types and Values</h2>
<div class="refsect2">
<a name="GHmac"></a><h3>GHmac</h3>
<pre class="programlisting">typedef struct _GHmac GHmac;</pre>
<p>An opaque structure representing a HMAC operation.
To create a new GHmac, use <a class="link" href="glib-Data-HMACs.html#g-hmac-new" title="g_hmac_new ()"><code class="function">g_hmac_new()</code></a>. To free
a GHmac, use <a class="link" href="glib-Data-HMACs.html#g-hmac-unref" title="g_hmac_unref ()"><code class="function">g_hmac_unref()</code></a>.</p>
<p class="since">Since: <a class="link" href="api-index-2-30.html#api-index-2.30">2.30</a></p>
</div>
</div>
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